Contribution to the study of the pseudobinary Zr1Nb–Oxygen phase diagram by local oxygen measurements of Zr1Nb fuel cladding after high temperature oxidation

Depth profile of oxide volume fractions of Zircaloy-2 in high-temperature steam: An in-situ synchrotron radiation study

“…We do not see a sudden drop (an edge) of the amount of oxide phase in depth direction, although the SEM/OM metallography shows different microstructures in different layers/ regions [5,6,8,22,35]. The observation in the current study is the insitu X-ray diffraction measurement when the specimen was under steam oxidation was different from the SEM/OM examinations on the post-oxidized specimens, which were often quenched or natural-cooled from the high-temperature exposure.…”

“…Previous studies on high-temperature steam-oxidized Zr alloys using SEM and OM revealed four major regions with different microstructures: (1) oxide, (2) a-Zr(O), (3) (a + b) Zr, and (4) prior b-Zr/b-Zr [5,6,8,22,35]. Depending on the temperature (particularly above the (a + b)/b transformation temperature) and the time of steam exposure, the region of (a + b) Zr may not be observed in the SEM examinations [6,8].…”

“…O, Nb, and Tin, etc. (mainly oxygen in the oxidation studies [22]), the higher temperature generally promotes the transformation and stabilization of the b phase. Since the temperature of this study was 800°C, which is in the middle of the a + b range, the extended distribution of both phases can be expected.…”

“…Negyesi et al combined secondary ion mass spectrometry (SIMS), wavelength dispersive spectroscopy (WDS), thermal energy analyzer (TEA), and microhardness measurements in order to investigate the Zr1Nb-O phase diagram [22]. Raman spectrometry was employed by Bouvier et al [2] and Kadiri et al [4] in order to study the pressure-temperature phase diagrams of zirconia and its breakaway oxidation phenomenon (which was also examined by atomic force microscopy), respectively.…”

Effect of creep and α-Zr ↔ (α + β)-Zr transition in Zr1Nb cladding on texture analyzed by neutron diffraction

“…The different tensile stress (10 MPa for E and 5 MPa for F) did not affect the phase transformation, as was proven for the Zr1Nb alloy in [17]. Under those conditions, the boundary between a and b phases is not direct, there is a transition area, where the mixture of a-Zr and b-Zr is at equilibrium, as can be seen in [18]. It must be pointed out that after the end of the creep test the samples were left to cool down in the furnace and all samples underwent recrystallisation (however less pronounced in tube B), but only tubes E and F underwent phase transitions: first a-Zr ?…”